The guiding catheter is a catheter, which guides a PTCA catheter or the like for treating the coronary arteries of the heart when inserting the PTCA catheter or the like to a target site.
A guiding catheter with a smaller outer diameter is expected in order to reduce the burden on a patient (specifically to reduce the size of an incision of an insertion portion of a blood vessel and to reduce friction between the guiding catheter and the blood vessel). In contrast, a PTCA catheter which is used for treatment and is a larger size is expected in order to exhibit a sufficient effect in a treatment site. For this reason, a guiding catheter with a larger inner diameter is expected.
In recent years, a guiding catheter having an outer diameter of, for example, 6 Fr (2.06 mm) or 7 Fr (2.36 mm) has mainly been used. A guiding catheter with a smaller outer diameter is less invasive with respect to a patient, but the procedure becomes relatively difficult. In addition, if the wall thickness of a guiding catheter is made thin while maintaining the outer diameter of the guiding catheter to be fixed, the tube wall naturally becomes weak and crushing or breakage (kinking) can be easily caused.
In addition, kink resistance improves as a catheter shaft portion of a guiding catheter or the like is flexible, but high pushability (transmission performance of pushing force) or high torque transmission performance is not obtained while inserting the guiding catheter into a blood vessel. For this reason, it is difficult for the catheter having a flexible catheter shaft portion to pass a meandering blood vessel. In addition, in a case where a distal portion of a catheter has a curved shape, if the section provided with the curved shape in the distal portion is too soft, a distal end of the catheter can be easily deviated from a coronary artery hole due to an operation, such as insertion of a PTCA catheter or the like, of a device after the distal end of the catheter is engaged with the coronary artery hole through the aorta.
For this reason, as a catheter which has a small outer diameter and has high pushability and high kink resistance, a catheter which is provided with a reinforcement layer formed of a plurality of reinforcement wires between an inner layer and an outer layer is disclosed in JP-A-2006-288670.
In the above-described catheter disclosed in JP-A-2006-288670, a mesh-like reinforcement layer is provided between the inner layer and the outer layer. Therefore, the area on which the inner layer and the outer layer come into contact with each other is narrow, and thus, bonding strength between the inner layer and the outer layer is not relatively high. For this reason, structure disorder such as separation at an interface between the inner layer and the outer layer can occur relatively easily due to application of flexural stress, torsional stress, or the like during use of the catheter, and therefore, the physical properties of the catheter easily change. When the physical properties of the catheter change, the flexibility of the catheter can deteriorate, and therefore, kinking may easily occur in the middle of use, or the performance such as pushability or torque transmission performance can deteriorate.